PDAs (personal digital assistants), personal computers, ATMs (automatic teller machines), and other various types of electronic devices have, for example, operation buttons or keyboards, touch panels, and other user interfaces. Users use these user interfaces to perform operation inputs to the electronic equipment, such as inputting words and selecting a processing to be executed.
In the case of a portable electronic device provided with a keyboard or operation buttons, however, keys or operation buttons are of a reduced size, weight, and thickness to conform with an overall reduction in size, weight, and thickness of the device; and, consequently, a user may not be able to feel that a button has been fully depressed. To confirm if depression of keys or operation buttons has been received in a portable electronic device, a user must view contents of a display of a screen of the device.
In the case of an electronic device provided with a touch panel, a user uses his or her fingertip or an attached pen to operate a touch panel. However, if the fingertip or pen is not properly pointed at the touch panel, or the touch panel is not pressed with sufficient force, the operation will be invalid. To confirm whether a touch operation on a touch panel has been received by an electronic device, as in the above case, a user must view contents of the display.
There are other types of electronic devices which report to a user, by way of a beep sound and the like, that an operation input has been received, but such an audio report is almost completely ineffective in a noisy environment such as in a street.